1. Technical Field
The present invention relates to a vacuum vapor-deposition system which is suitable for production of epitaxial layers in accordance with the molecular beam process.
2. Background Art
In the vapor deposition of thin layers of high uniformity, as are necessary e.g. in molecular beam epitaxy and also in the manufacture of interference filters and the like, measures are necessary to equalize the unavoidable locally different densities of the atomic or molecular beams going out from the vapor-deposition-material source or sources. In the known vapor depostion systems there is provided for this purpose a substrate holder which gives a simple or complex rotation of the substrate to be coated, while the evaporator or vapor-deposition-material source is held stationary in the vacuum chamber below the substrate support. The vapor-deposition-material source, which e.g. can consist of so-called Knudsencells, are in general provided at any given time with a movable shutter or other shield mechanism, which can be arranged between the source in question and the substrate, in order to release the beam of evaporation material directed from the source in question to the substrate.
A device for thermostating the substrate is usually arranged on the substrate holder. One disadvantage of the known vacuum vapor-deposition systems is that the mechanisms for movement of the substrate are exposed to the ultra-high vacuum and deposits from the evaporated material; moreover, the thermostating of the moveable substrate holder is difficult. Finally, the uniformity of the deposit often leaves much to be desired.
Accordingly, the problem underlying the present invention was further to develop from a vaccum vapor-deposition system of the type mentioned at the beginning hereof, so that a very high uniformity of the vapor-deposited layers would be achieved, and the agitating mechanisms necessary for rendering the deposit uniform could be arranged outside the vacuum.